How to define variable inlet velocity in SimScale in Transient analysis?

If your variable velocity can be represented by a series of constant values at specific time intervals, you can define a piecewise constant inlet boundary condition in SimScale. Here's the approach:

• Divide the total simulation time into smaller time steps where the inlet velocity can be considered constant.
• Set up a transient simulation in SimScale.
• Under the boundary conditions section, define an inlet for the fluid domain.
• In the inlet properties, you can specify the velocity value for each time step. SimScale will apply the specified velocity throughout that time interval.

User-Defined Functions (UDFs) for Complex Variations:

For more complex variations in inlet velocity, SimScale offers User-Defined Functions (UDFs). UDFs allow you to write custom code that defines the velocity based on simulation time or other parameters.

This approach requires some programming knowledge and familiarity with SimScale's UDF implementation. Here's a general idea:

• Develop a UDF that calculates the desired inlet velocity based on the current simulation time or other relevant variables.
• In SimScale, under the boundary conditions section, define a UDF-based inlet for the fluid domain.
• Link your developed UDF to this boundary condition.

Additional Resources:

• While SimScale doesn't have an official documentation on defining variable inlets for transient simulations, you might find relevant information in the user forums or discussions. Searching for terms like "variable inlet velocity" or "UDF transient inlet" on the SimScale website could lead to helpful insights from other users.
• Consider contacting SimScale support to inquire about potential future functionalities or alternative approaches for your specific case.

Can I import CSV file as a inlet velocity profile in SimScale?

No, SimScale currently doesn't directly support importing a CSV file to define a variable inlet velocity profile for transient simulations.

There are limitations with CSV import for velocity inlets:

• Limited Data: CSV files can only represent a single snapshot of the data at a specific time. This wouldn't capture the time-varying nature of a transient simulation.
• Data Interpretation: SimScale needs information about the specific location within the inlet where each velocity value applies. A simple CSV wouldn't provide this information effectively.

Here are some alternative approaches to consider:

1. Piecewise Constant Velocity: As mentioned earlier, you can create a piecewise constant profile. Prepare your CSV with columns for time steps and corresponding constant velocity values. Then, manually set these values in the SimScale inlet boundary condition for each time step.

2. UDFs for Complex Variations: If your velocity variation is complex, consider User-Defined Functions (UDFs). This requires programming knowledge to create a function that calculates the velocity based on simulation time or other parameters.

3. Alternative Software: Explore software that might offer direct CSV import for transient velocity profiles. However, ensure compatibility with your overall workflow.

While SimScale doesn't support direct CSV import, the piecewise constant approach or UDFs can be workarounds depending on your specific needs.